Having stripped the tank has caused me to observe the tetras in a new sparse plant situation and now I see what they like. They like little patches.

A male takes up a patch to call his own and declares its intention to invite all females but no other males allowed. So there are miniature chase flurries around the patch to get interloping males to find their own patch.

When a female takes up the invitation they are truly scampy little things. The pair tumble in the bushes as it were twisting and turning in mad orgiastic piscine ecstasy. They are delightful to watch, you can tell they're having fun, but that appealing activity attracts attention and now the space is unguarded. Sometimes more fish join in the fun going on momentarily in the little patch. It's all very fast.

As the overseeing gardener it is my job to provide more and better patches. Different kind of patches so they can make up their little fish minds which patch they like best. There is a lot of room down there for variety.

To this end last night I popped a sum for aquatic foreground plants. Six different kinds. Seemed strange to have all foreground plants but some of them do tend to take over with strong light and CO2. They each have interesting unique characteristics. One type tends to float but also roots so it is held down and placed where you want this sort of thing to go. With the conditions described it produces oxygen visibly. Tiny bubbles pearl, one each for each tiny leaf, it takes awhile to develop after the lights come on and it is visually stunning. The fish are all the eh being tiny jewels themselves.

IIRC, birdbath water should be no more than three inches deep and the basin should have a rough surface so young birds don't get in over their heads and if they do, won't be on a slippery surface and unable to get out.